Grinder gas, that is the gas which is released from roasted whole coffee beans when their internal cell structure is disrupted, such as during grinding of the beans and which also continues to evolve from the disrupted and/or fractured beans for a short period thereafter, has long been recognized in the art as a highly desirable natural coffee aroma. The collection and stabilization of this aroma has, however, proven to be a difficult undertaking.
The use of grinder gas aromatics as a means to enhance the jar aroma of a soluble coffee powder is disclosed in U.S. Pat. No. 3,021,218 to Clinton et al. which aromatizes the jar headspace and U.S. Pat. No. 2,306,061 to Johnston which condenses grinder gas aromatics onto chilled soluble powder. The use of grinder gas condensates which are added to a liquid extract and dried in order to produce an improved cup aroma when the powder is dissolved in hot water is disclosed in U.S. Pat. No. 3,244,533 to Clinton et al. which homogenizes coffee oil in extract and then adds condensed grinder gas aromatics and in co-pending, commonly-assigned patent application, Ser. No. 252,883, filed May 12, 1972, U.S. Pat. No. 3,821,447 which mixes condensed grinder gas with a liquid glyceride which mixture is then processed to remove excess water, such as by centrifugation, prior to being added to liquid extract which is then freeze dried.